Bathroom Remodel - shower fixture

We are getting ready to remodel the upstairs bathroom and I have some preliminary questions that will inevitably guide what comes next/first/etc.

Background:
I have just moved to Southern Louisiana and am living with my handsome fella who has been living in his current house for 10 years or so. It is estimated that the house is around 25 years old. My fella has performed no modifications on the house and is a pretty conservative and cautious guy. I, on the other hand, have lived in apartments most of my adult life and although I love to do stuff on my own, I have not had a lot of first hand experience. I research a lot and then just give it a go. It may take longer but I am usually pretty patient. My fella? not so much. We are about to remodel the main bathroom that he uses every morning and I am trying to get everything lined up before we start to minimize any "gotchas"... although I know that is not 100%possible.

First question:
Currently there is a tub with a synthetic marble (or something like that) surround that goes up to about 1.5' from the ceiling. We would like to remove the surround (that has started to bow a bit) and tile in the area. There will be questions about tiling around the window that I will probably take over to JohnBridge but before I get to that, I really think I want to replace the current shower/tub valve and fixture while the wall is already torn out. The current setup is a single knob Nibco that you just turn and it goes from cold to hot and controls the flow all in one function. There is no "turn to get to temperature and then lift to control water flow). Then there is the "stick" control on the tub filler that when you pull it up, it redirects the water to the shower head. I think we would like to replace this one with at least the same functionality. It MAY be nice to have a separate function that would allow us to control an additional hand-held shower unit - maybe on a slider bar - that will allow my fella to use the hand-held part as a massage shower for his lower back. We have had no problems with the existing Nibco valve but I figure it will eventually need to be replaced and it would be better to do that now. I had to talk the fella into this as he typically does not want to mess with stuff that is working (and I understand that). But now just seems to be the best time to take this on as well.

1) When I go looking for parts, I really do not know the names of what I need to get. I THINK I need a new rough-in valve as the Nibco is 25 years old. We have not had any problems with leaks or anything like that but I figure it will eventually go bad before someone decides to re-tile. Could anyone recommend a good valve to let me do what I think I want

2) I am interested in at least trying to do the plumbing work myself (if it is just sweating a few joints). Am I just asking for too much trouble there? I would love to take the synthetic marble down and take a good look at what I have right now but that means the bathroom would be out of service for even longer than it already will be if I were just going to tile.

The plumbers here often recommend the Delta 1700 series valve. You can use either a pressure balanced valve or a thermostatically controlled one with that rough-in if I remember right. Your old valve probably does not meet current safety anti-scald regulations.

I put in Grohe valves when I remodeled...they had an externally mounted valve (there is no rough-in, the only thing that goes through the wall is the hot and cold supply lines). It fit in where I was working since there was no access behind (air ducts and a pocket door). It includes both the tub spout and the divertor for a hand shower. I do not have a fixed showerhead, only the hand-held on the adjustable bar.

I suggest that you go to a good local plumbing supply place that has a showroom. They have a much better selection than the big box, and their prices are usually competitive. But they will also have an expert there who can get you exactly what you want, and if necessary order it for you. There is a ton of shower units that you won't find elsewhere, and they can tell you the pros and cons, especially with your rough-in.